[Effect of isosorbide dinitrate on platelet aggregation and production of thromboxane B2].
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Biomedical subjects
Publications and source records attributed to F Crea.
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We studied the hemodynamic effects of dobutamine in 10 patients with severe chronic heart failure due to congestive cardiomyopathy in 5, to ischemic heart disease in 4 and to hypertensive cardiomyopathy in 1. Dobutamine was injected during three periods of 30 min each alternated with equal periods of placebo at doses of 2,5-5 and 7,5 mcg/Kg/min respectively. The most favorable hemodynamic effects, obtained at an infusion rate of 5 mcg/Kg/min, was characterized by a significant inn 4 and to hypertensive cardiomyopathy in 1. Dobutamine was injected during three periods of 30 min each alternated with equal periods of placebo at doses of 2,5-5 and 7,5 mcg/Kg/min respectively. The most favorable hemodynamic effects, obtained at an infusion rate of 5 mcg/Kg/min, was characterized by a significant increase of the cardiac index and of the left ventricle stroke work index, accompanied by a significant decrease of the left ventricular filling pressure and of the systemic and pulmonary vascular resistance. The hemodynamic monitoring showed that the pharmacological effects of the drug subsided about 5-10 min after the interruption of infusion. At the infusion rate of 7,5 mcg/Kg/min we observed a significant increase of premature ventricular beats in 3 patients. We conclude that dobutamine at the dose of 5 mcg/Kg/min shows a powerfull positive inotropic action not accompanied by apparent side effects.
Three experiments have tested for the existence of laterality effects in iconic storage by employing a Sperling partial-report paradigm and lateralized presentations of alphabetical or pattern material. Even though an overall laterality effect was found in favor of the right visual field for the alphabetical material and in favor of the left visual field for the pattern material, the amount and time decay of partial-report advantage was similar in the two visual fields. These results indicate that hemispheric asymmetries occur beyond the iconic stage of visual information processing.
In a simple reaction time task, key-pressing responses to unpatterned light stimuli presented in the right and left visual fields were faster for the hand ipsilateral to the visual stimulus than for the hand contralateral to the stimulus. The superiority of the ipsilateral reactions was seen also when responses were made with the hands crossed, so that such a superiority cannot be attributed to spatial compatibility between the side of the stimulus and the position of the response device. Similar results were obtained in a reaction time task of the Donders's c-type. It is argued that these laterality effects in visuomotor reaction time tasks are best explained by the anatomical relationships between the visual fields, the cerebral hemispheres, and the hands. The possible interaction between these effects and the effects of spatial compatibility between side of stimulus and side of response device are discussed in relation to reaction time tasks of the Donder's b-type.
The mechanism of ergonovine-provoked coronary vasospasm is poorly understood. We tested the effect of ergonovine in perfused hearts from normal and cholesterol-fed (18 weeks, 2% cholesterol diet) rabbits in a constant-flow Langendorff perfusion. Aortic perfusion pressure was monitored to measure coronary vascular resistance, and left ventricular pressure was measured with an isovolumetric balloon in the left ventricle. Control coronary vascular resistance was 1.12 +/- 0.11 mm Hg/ml/min in hearts from normal rabbits and 1.53 +/- 0.16 mm Hg/ml/min in hearts from cholesterol-fed rabbits (n = 9 each, mean +/- SEM, p less than 0.05). The cholesterol content of aortae from cholesterol-fed rabbits was markedly increased (432 +/- 85 mg/g protein vs. 14.9 +/- 8.2 in controls, p less than 0.001; for coronaries: 396 +/- 136 mg/g protein vs. 125 +/- 25, p less than 0.05). In both groups, increases in coronary vascular resistance were observed with vasopressin (40 IU/l) and phenylephrine (30 microM) and decreases with adenosine (10 microM), isoprenaline (0.1 microM) and 30 sec stop-flow (all p less than 0.05). Ergonovine maleate (10 microM) and serotonin (10 microM) did not increase coronary vascular resistance. Although in whole heart perfusion small changes in the caliber of epicardial vessels may not be detectable, changes severe enough to produce measurable changes in total coronary resistance were not found. Therefore the absence in our model of an increase in coronary vascular resistance after ergonovine is not compatible with a local direct mechanism in epicardial arterial wall, even when sensitized by a high cholesterol diet.
Drug craving is an irresistible urge that compels drug-seeking behavior, and which often accounts for relapse among treated cocaine users. A cocaine craving scale that has proven reliable and practical in clinical treatment research with cocaine-using subjects is presented. It assesses intensity, frequency, and duration of this entirely subjective phenomenon. Data from 234 scales completed by 35 patients in treatment showed that craving for cocaine was of variable intensity, experienced relatively few times per day (zero to two), and of short duration (less than 20 minutes). Internal consistency among the three scales was robust, shown by a standardized item alpha of .826. The use of this scale should allow for each component of craving to be studied separately.
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